<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    .one{
        color:red;
    }
    </style>
</head>
<body>
    <p id="test" class="one">hello world</p>
    <script>
        // getAttribute--设置属性
        // removeAttribute--移除属性
    var test=document.getElementById("test");
    test.onclick=function(){
        this.removeAttribute("class");
    }
    </script>
</body>
</html>